[Haskell-cafe] Implicit parameters and Arrows/Yampa?

Derek Elkins derek.a.elkins at gmail.com
Mon Jan 7 12:57:53 EST 2008

On Mon, 2008-01-07 at 17:24 +0100, Peter Verswyvelen wrote:
> Derek Elkins wrote:
> > Implicit parameters add an extra argument to a function conceptually.
> > What you need is to "add an argument" to "SF" which implicit parameters
> > don't know how to do since SF is just some data structure.  One way to
> > deal with this is the way you deal with the same problem in Haskell
> > without implicit parameters. (I never use implicit parameters).  In that
> > case you would use the Reader monad (transformer).  Similarly, you can
> > use an equivalent Reader/Environment arrow transformer.
> >   
> Nice, I did not know that monad yet, thanks!
> But can it be combined together with the arrows do/proc syntax? How 
> would that look like?

Claude Heiland-Allen gave an example, I just want to clarify.

The only reason I referred to monads is for analogy.  You don't use the
Reader monad or Reader monad transformer, you use an idea analogous to a
monad transformer called an arrow transformer, which is what Claude

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